Roy wrote:
> Hello group
> Recently I was dismayed why my USB drive was not recognized anymore
> by window explorer. Therefore if I plug it on the USB slot it does
> nothing. I searched the web for some ideas and came from this fellow
> which states:\
>
> 'A user of a company I know recently told me the following experience
> he had with a USB flash drive. The user traveled a lot and had a
> laptop that he used to connect to the company's network when he was in
> the office. And he was used to plugging his flash drive into the USB
> slot on his laptop so he could transfer files to another machine he
> used at home. But one day he came into the office, connected his
> laptop to the network, plugged in the flash drive and nothing happened
> -- normally an Explorer window would open displaying the contents of
> the drive. This was disconcerting, so he opened My Computer and
> discovered that the USB drive wasn't there. Puzzled by this, he took
> out another flash drive from his pocket and tried it, and this time it
> worked fine so he knew at least the problem wasn't with his computer.
> He was just about resigned to throwing out his first drive when he
> decided to send me a quick email detailing the problem. My immediate
> reaction too was that it was that the drive had failed, but then I
> thought about it some more. One of the key steps in troubleshooting
> problems is to ask what just happened. The drive failure had occurred
> after he connected his machine to the network, so could it be an issue
> with the network? I emailed back and suggested he disconnect his
> laptop from the network and try the flash drive again, and a short
> time later I received an email saying the drive now worked!
> Then it dawned on me. I told him to remove the drive, connect to the
> network and open My Computer again and look for something different.
> He did this and told me there was a new mapped network drive that he
> hadn't seen before. Aha! The network administrator must have modified
> their logon script to map a new drive on users' computers, and this
> new mapped drive probably assigned the very same drive letter that
> this particular user's laptop had previously assigned to his first USB
> drive. I told him to plug the USB drive in again, open Computer
> Management, and change the drive letter of the USB drive. He did this,
> and right away an Explorer window opened displaying the contents of
> his USB drive. Problem solved'
>
>
> Since I have never done such things these ideas sound strange to me.
> Meaning if the drive is malfunctioning it might have something to do
> with such and not a hardware fault.
> Although I was not using a laptop but just a desktop PC.
>
> I did found the computer management ( local) and had viewed the disk
> management on the right pane.
> Indeed there are letters that indicates one drive say for example
> Drive D and drive C which is easier tounderstand as well asthe Drive E
> and F and so forth. Previously the Flash drive was recognized as
> Drive G and J as well as drive H for another External hard drive.
> But now it does not recognized my flash drive.
> What I don't understand is why window explorer does not recognize my
> USB flash drive but still do with the other drives.
>
> Early this morning I was plugging these drives to the networked
> computer in the internet cafe and immediately it was not recognized
> and this kept me worried so when I arrived home I immediately plugged
> it and there the flash drive is not functioning or being recognized
> anymore.
> Could somebody offer me their advice how to sort this out
>
> What is going on?
>
> TIA
> Roy
>

Uwe Sieber has a web site, with that kind of information on it.

http://www.uwe-sieber.de/usbtrouble_e.html

From a hardware perspective, you can verify that the plugged in
device is being detected (communicated with), via UVCView program
from Microsoft. (Use the upper right hand link, to download an
executable for Windows 32 bit OS.) This is an archived web page,
as Microsoft has taken down the download page. There have been
several versions of programs that look like this one, and so far,
this one is the most capable. (Some of the originals, had limits
on the number of ports they could handle.)

http://web.archive.org/web/200705160...VCViewdwn.mspx

If the physical layer is working, and the USB device can be
enumerated, and fill the window with data, then the problem
must be at a higher level in software. (In the picture here,
you can see VID/PID 0x0ECD 0xA100 device has been detected, and
the presence of the Endpoint Descriptor presumably means a
communications path is set up.)

http://www.die.de/blog/content/binary/usbview.png

For resetting the USB stack, usbman.com has a page describing a
procedure to do in safe mode. But this doesn't necessarily fix
everything. There are also instances where a driver cache is
corrupted, or the registry is locked to updates, that might
cause a procedure like this to not fix anything. But in those
cases, searching on the exact error text, will likely lead you
in the right direction.

http://www.usbman.com/Guides/Cleanup...afe%20Mode.htm

HTH,
Paul